Select Component page doesn't detect changes further though the installation process if you click back and change the checkboxes on the select component page.
e.g. Tutorials is checked, click next, click back, uncheck Tutorials, click next... you eventually get to the asking about where to install Tutorials and Next doesn't work.
I'm installing SoapUI-4.5.1.dmg on Mountain Lion Mac OSX 10.8.
Work around, close installer, get select the right options on select components the 1st time through.